A Transparent Elasticized Adhesive Occlusive Compression Bandage for Use as an Arterial Tourniquet

Randomized Sequence, Assessor-Blind, Cross-Over Study of a Windlass Tourniquet, a Pneumatic Tourniquet and an Elastic Adhesive Bandage for Use as a Tourniquet

This cross-over study of twenty five (anticipated) healthy human subjects will utilize two active control devices, and two different widths of the investigational device. One active control is representative of the usual care tourniquet applied in hospital settings. The second active control is a windlass tourniquet representative of the pre-hospital and military usual care tourniquet device. Two inch and four inch widths of the investigational device will be evaluated. The purpose of this study is to characterize and compare investigational and control tourniquet safety and efficacy. All tourniquets will be applied to the upper thigh. Efficacy data is provided by the presence or absence of popliteal flow when assessed with ultrasound. Mapping of interface pressures between the skin and the tourniquet will provide safety data. A minimum washout of five minutes will be allowed between tourniquet applications. All interventions will be applied in one visit. No follow up visit is anticipated.

This is a small study of 19 participants conducted over only two days. All data for this study is collected by the study. Tourniquet application: All tourniquet applications conducted with the participant seated on the edge of an exam table with one leg hanging off the side, and the leg for tourniquet application extended outward, with the mid calf resting on a support. This position permits access to the popliteal artery for ultrasonography while the investigator has access to apply the tourniquet. The lower edge of each tourniquet is aligned just above the middle of the thigh. All tourniquets are applied over the pressure mapping sensor. The sensor is slightly thicker than denim jeans. Extra care must be taken to ensure that the material of the sensor does not interfere with removing the slack from the windlass tourniquets before turning the windlass to apply final pressure. When a second windlass tourniquet is to be applied it is applied just above or proximal to the first windlass tourniquet. The windlass of each tourniquet are located as far from each other as possible. Meaning that if the windlass of the first tourniquet is the twelve o'clock position then the windlass of the second tourniquet is positioned at the six o'clock position. The strap of each tourniquet cannot slip over the windlass of the other. This 6 and 12 positioning prevents the strap of the second windlass tourniquet from slipping over the first as it is tightened. When the tape tourniquet is applied, it is elongated, stretched as it is layered over the preceding layer with at least one half over lap. The tape tourniquet used in this study is similar to, but not the same as the product called manufactured by Entrotech, called "Battle Wrap." Results similar to this study should not be expected with the "Battle Wrap" product.

tourniquet, arterial, pre-hospital, SOFTT-W, Battle Wrap, windlass, exsanguination, hemorrhage, amputation

All participants randomly allocated to receive all interventions. Pneumatic Tourniquet: The Automatic Tourniquet System (ATS) 1500 by Zimmer (formerly Aspen Labs) is a pneumatic tourniquet that is typically used in surgical settings, and is representative of best outcome under the ideal circumstances of a controlled environment. The 10 cm (4 inch) wide cylindrical cuff was used for all participants.

Windlass Tourniquet with a 3.8 cm (1.5 inch) wide strap is representative of the typical use device in civilian prehospital and military combat environments. In accordance with current prehospital guidelines: If distal perfusion is observed after One Windlass Tourniquet is applied then a second windlass tourniquet will be applied immediately proximal to the first windlass tourniquet so that the participant has Two Windlass Tourniquets applied.

Tourniquet Tape 10 cm wide is a highly elastic transparent occlusive tape that is expected to create sufficient circumferential pressure to occlude arterial blood flow when tightly wrapped around a limb. The tape should be applied in mostly overlapping layers. The final wrap should be applied without tension to prevent the elastic tension from causing the tape to unwind itself.

Tourniquet Tape 5 cm wide is a highly elastic transparent occlusive tape that is expected to create sufficient circumferential pressure to occlude arterial blood flow when tightly wrapped around a limb. The tape should be applied in mostly overlapping layers. The final wrap should be applied without tension to prevent the elastic tension from causing the tape to unwind itself.

One Windlass Tourniquet 3.8 cm (1.5 inch) wide. A Special Operations Forces Tactical Tourniquet Wide (SOFTT-W) will be used for the windlass tourniquet. One windlass tourniquet will be applied to the middle upper thigh.

Two Windlass Tourniquets will be applied by applying a second 3.8 cm (1.5 inch) wide windlass tourniquet immediately proximal to the first windlass tourniquet.

Tourniquet Tape is 5 cm (2 inch) in width. Tourniquet Tape is a highly elastic transparent occlusive material that can create circumferential pressure when stretched and wrapped around a limb. The tape should be stretched and overlapped by at least half the width as it is applied. The final wrap should be applied without tension.

Tourniquet Tape is 10 cm (4 inch) in width. Tourniquet Tape is a highly elastic transparent occlusive material that can create circumferential pressure when stretched and wrapped around a limb. The tape should be stretched and overlapped by at least half the width as it is applied. The final wrap should be applied without tension.

Duplex and color flow ultrasound are used to assess distal blood flow at the popliteal artery for 1 sustained minute following the application of a each tourniquet intervention to the middle upper thigh. If no flow is observed for 1 sustained minute then it is considered successful occlusion. A still image is then saved for later evaluation by the blinded outcome assessor. The 5 cm tape was discontinued after the 4th participant because the tape was considered to unacceptably narrow after stretching and this was considered a mechanical failure even if occlusion was observed. Therefore the 5 cm tape data was not evaluated by the radiologist.

Duplex and color flow ultrasound are used to assess distal blood flow at the popliteal artery for 1 sustained minute following the application of each tourniquet intervention to the middle upper thigh. If no flow is observed for 1 sustained minute then it is considered a successful occlusion. This assessment was made by the investigator and ultrasonographer applying the intervention.

Inclusion Criteria: Upper thigh circumference greater than 61 cm or 24 inches. Upper thigh circumference greater than the 50th percentile based on available anthropometric data. Exclusion Criteria: Currently taking medications for the treatment of hypertension. Cardiac, renal, pulmonary, hepatic or hemologic disease or disorder. Patients with signs or symptoms of vascular insufficiency. Specifically, patients with any history of non-healing wound, ulcer, blood clots or peripheral vascular disease will be excluded. Any coagulation disorder, prior thrombotic or embolic events such as a deep vein thrombosis. Sickle cell. Diabetes mellitus Rheumatic arthritis or other auto immune disease. Major surgery, significant traumatic injury, within 60 days trial. Skin grafts on lower extremities. Known or observed neurological symptoms, to include peripheral neurological symptoms or deficits. Pregnant women, and women who suspect themselves to be pregnant are not eligible for this study. Any known malignancy. Claudication

Individual participant data will be de-identified and consolidated into one Excel file and made available online. Still ultrasound images used for primary outcome assessment will be consolidated into one pdf and made available online. Individual participant data that is not supported by clinicaltrials.gov will be posted with Zenodo or by other means. The intent to release de-identified data was disclosed to each volunteer during the informed consent process.

De-identified IPD from this study will be public domain. Identifying information and records will be held confidential.

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